"Over the years, it's become more acceptable – people should be proud of who they are," he said. "If you want to be a Christian and go to church, that's fine, but there should be institutions for people who aren't religious."

More Americans are claiming no religion and many have taken on more outspoken and public campaigns. According to the 2008 American Religious Identification Survey, 15 per cent of Americans are part of the non-religious population, or "nones", up from 8.2 per cent in 1990.

SSA, meanwhile, provides a social network for students who are seeking an alternative to campus religious ministries, the alliance says.

The UK has seen a similar growth in secular student groups. The National Federation of Atheist, Humanist and Secular Student Societies (AHS) announced in April that would expand its network of atheist groups in schools. In the summer, it ran its first atheist summer camp for children with the aim of encouraging children to assess different beliefs critically.

Between 2007 and 2009, the number of AHS campus groups rose from seven to 25.